Fluid-pressure hammer



June 3, 1930. V M, MAXIMIUA N 1,761,734

FLUID PRES SURE HAMMER Filed May 20, 1925 Patented June 3, 1930 N D L TES PA mr' FF'ICE' ax MAXIMILIA or onrcneo, ILLINoIs, AssIeNon TO CHICAGO PNEUMATIC 'rooI. I COMPANY, or NEWYORK, N. Y., AcoRroRATIoNor NEW JERSEY rnurn-rnnssunn HAMMER I V Appl ication filed May 20,

This invention relates to pneuma'tictools of the percussive type and more particularly to improvements in the parts thereof which have to do with the control and distribution of the motive fluid. The invention has particular reference to percussive machines hav ing a sleeve valve through which or into which the hammer piston passes during its reciprocation, suchas riveting and chipping hammers. I V

' In ractice sleeve valves of thetype described are disposedfor reciprocatory movement within valve blocks remo'vably secured in the rearends of the hammer cylinders. The valve blocks are. ordinarily of soft steel and the rapid movement of the hardened valve averaging a thousand'strokes per minute, which is two thousand movements per minute, produces rapid wear of the block. When the wear causes .suliicientv leakage past the valve to interfere with the proper operation of the hammer, the valve is taken out and an oversize valve is inserted. It is not unusual to use eight different sizes of oversize valves before anew block isus ed. The spare parts needed to make these frequent changes in valves and renewal ofvalveblocks inaddition to the time and labor. consumed thereby arelargely responsible for the high expense of upkeep of such tools] u I Attempts haveheretofore been madeto reduce the wear in such tools by hardening the valve block. suchattempts have not been successful commercially even when-the block has been made in two substantially equal 7 parts since the thick'walls of the valve block and-the numerous ports and passages therein produce uneven expansion when heated and the strains thus produced result in distortion of the parts and an undueamount of breakthe efliciency of machines. of the class de-- b n n l I l u u One ob ect of the invention isto increase scribed and to decrease the expense of main tenance by reducing the wear in the valveblock. Another object is to secure the above result in old as well as new tools. Other ob jects will be apparent from the detailed description which follows. o

The invention comprises the use of a sta:

1925. Serial No. 31,504.

tionary wear resisting member between the valve and the valve block. This member may take the form of a hardened sleeve or liner with relatively thin walls inserted within the valve block. This sleeve has ports registering with the ports and'passages of the valve block and makes alight pressfit with the latter. 7 V

When using the hardened sleeve in a valve block comprlsing' a case and a narrow lid in the valve' case.

Thev embodiment of the invention chosen for the purpose of illustration discloses in Figs; 1 and 2 a Boyer riveting hammer conforming substantially to the disclosure of the Boyer'Patent No; 917,242 of April 6, 1909, savefor the details of the valve block to which the present invention pertains. A detailed description of-the hammer and its manner of operation is unnecessary but is briefly cle- SCIlbGdas follows: The hammer comprises a cylinder A in which reciprocates a piston B imparting blows-to the working tool or rivet setG; Inserted into the enlarged borea'of the cyllnder as a unit is a valve block contain- *ing the sleeve valve D which controls' the ports and-passages of the valve block and reciprocates intimed relationwiththe move mer ts-of the piston B. The inner bore of the *valve' block' and valve D form an extension o'f"the"pisten chamber, the valve block being retained in place in the usual mannerby the handle"; which has threaded engagement with the "cylinder In Fig. 1' the piston is ,on its working stroke with the motive fluid passing from the supply duct 6, through pas sages f and inlet ports 9 to drive the piston forward and the air in advance of the piston is exhausted from the front of the piston chamber through passage h, groove 2', ports j, the central groove of valve D, ports is, and exhaust passages Z. When piston B passes beyond the outlet port of passage m the valve shifts rearwardly to the position shown in Fig. 2 cutting off the inlet ports g and opening the rear of the piston chamber to exhaust through the ports (Z in the valve, ports and exhaust passages Z. At the same time live motive fluid passes to the front of the piston chamber from the live air duct 6 through passages f, restricted passage 11., ports 0, the central groove of the valve, ports j, groove 2' and passage h. The valve is again shifted forwardly to the position shown in Fig. 1 by air compressed by the piston near the end of itsrearward stroke and by live air admitted against the rearmost flange of the valve through a restricted port 2), in the well known manner.

The novel form of valve block to which the present invention is particularly directed will now be described. Since it is impractical to harden the metal of the entire valve block due to the thickness of the walls made necessary by the numerous ports and passages, suitable means are provided for protecting against wear the portions of the valve block traversed by the valve, the extent of the movement of which is clearly indicatedby comparison of its positions in Figs. 1 and 2.

To this end the valve block is constructed preferably in three parts, namely, a valve case 4, a valve case liner 5, and a valve lid 6. The valve case 4 which is the largest of the three parts is of soft steel to facilitate the boring of the various ports and passages and its inner bore 4 at its left end as shown in Figs. 1 and 2 conforms to the bore of the piston chamber and provides the cushion chamber for piston B on its rearward stroke. The portion of case 4 in which valve D reciprocates is of in creased diameter and receives with a light press fit the valve case liner 5 which, as indicated in Fig. 3, is in the form of a sleeve with relatively thin walls and provided with ports arranged to register with the ports and passages in the valve case. The lid 6 covers the forward ends of the assembled case and liner and is formed with a projecting flange 6 which extends within liner 5 and serves as an abutment or stop for the forward flange of the valve D. The bore of lid 6 is slightly greater than the bore of the piston chamber and. serves as a bearing for the forward end of the valve. It is thus apparent that'all the wear of the valve block caused by valve D is taken by the liner 5 and lid 6. These parts are accordingly made of suitable wear resisting material. Since sleeve 5 and lid 6 are of a size and shape successfully to withstand heat treatment,they are preferably formed of hardened steel. In order to maintain the ports and passages of the valve block parts and of the cylinder in register a pin 9 is provided in which the assembled tool extends into sockets therefor in cylinder A and valve case 4 and through an opening in lid 6. Sleeve liner 5 is retained in proper relative position by a projection 62 on lid 6 extending into recess 5 therefor in sleeve 5.

The present invention is not confined in its use to new tools. Old tools can be readily modified to permit the use of the parts which protect the valve block against rapid wear. For this it is only necessary to bore out the old valve case to take the sleeve 5 and to use the hardened lid 6.

From the above it will be apparent that the present invention prevents excessive wear of the valve block by lining the same or forming the valve traversed portions thereof of wear resisting material, that the elimination of excess Wear heretofore obtaining at these points prolongs the eflicient and satisfactory operation of the tool, that the parts which will need replacing as a result of wear, particularly the liner 5 and lid 6, are relatively inexpensive, and that the replacement of a valve case on account of wear becomes entirely unnecessary since even an old valve case can be readily adapted to the use of the essential parts of the present invention by boring out the valve case to receive the sleeve liner 5.

I claim as my invention:

A separate valve unit for a fluid pressure tool comprising a valve block having ports and passages for the pressure fluid, a valve movable in said block to control said ports and passages, a removable lining sleeve between said valve and said block to take the wear of the valve and having ports and passages to register with those of said block, a renewable lid for said block, a dowel pin for maintaining said lid and said block in fixed relation, and a projection on said liner cooperating with a recess in said lid for maintaining said liner and said block in registering relation.

Signed by me at New York city, New York, this 13th day of May, 1925.

MAX MAXIMILIAN. 

